Observed $5/$10 hand

[iceman5]

I watched this hand and because the guys are regulars in my game, I want to get an opinion on this hand.

All players have about $1000

UTG limps, MP raises to $50. SB calls with QT of clubs. UTG reraises to $130. MP and SB both call.

SBs play is what Im asking about. I already think hes made 2 mistakes, but Im more concerned with the flop.

Pot is $400. The flop comes Ac Qh 4c. SB checks, UTG bets $100, MP folds.

UTG is going to have AA or KK here everytime. he limp reraised preflop which almost marrows to AA/KK already, but then he only bets $100 into a $400 pot. He either has KK and is afraid of the A, or he has a set of aces and doesnt want to scare anyone off. Either way, its a bad bet, but then the SB goes all in.

This cant possibly correct can it? If UTG has AA, hes not folding and QTs is a 2-1 dog.

If UTG has KK, he'll fold of course, but do you need to push to fold him? How about just calling getting 4:1 on your money?

The push is horrible, correct?